Styrene–substituted‐styrene copolymerization using diphenylzinc–metallocene–methylaluminoxane systems

Homopolymerization of disubstituted styrenes (2,4‐ and 2,5‐dimethylstyrene) and trisubstituted styrene (2,4,6‐trimethylstyrene) and their copolymerization with styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n‐BuCp)₂TiCl₂ and for half‐metallocene CpTiCl₃. The studied comonomers were found to be less reactive than p‐tertbutylstyrene, p‐methylstyrene and styrene. The results indicate that, even though the methyl group has I+ inductive effect, di‐ and tri‐methylstyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry     

Further studies on styrene/styrene derivative copolymerizations using combined diphenylzinc‐additive initiator systems

A combination of diphenylzinc, a metallocene and methylaluminoxane (Ph₂Zn‐metallocene‐MAO) is a suitable initiator system for the polymerization of styrene and for its copolymerization with para‐alkyl substituted styrenes. This paper reports new experimental results which reinforce our previous findings indicating that polymerization processes are initiated by monomer coordination to active species resulting from these particular combined systems. Polymerization propagates by a cationic pathway. Further to our previous observation that the I+ inductive effect of para‐substituents in styrene improves conversion to polymer, we now find that methyl substitution on the vinyl double bond of styrene, in spite of the I+ inductive effect and as a result of increased steric hindrance, makes the polymerization process difficult. On the other hand, the replacement of titanocenes by zirconocenes or hafnocenes generates Ph₂Zn‐metallocene‐MAO initiator systems which are also able to induce homo‐ and copolymerization, but with lower yields and producing practically amorphous polymers. The efficiency of our Ph₂Zn‐metallocene‐MAO initiator systems follows the order titanocene > zirconocene > hafnocene, at least for the studied metallocenes. Copyright © 2004 Society of Chemical Industry     

Copolymerization of styrene by diphenylzinc-additive systems. Part II: Copolymerization of styrene/1-alkene by Ph2Zn-metallocene-MAO systems

Summary The copolymerization of styrene with 1-alkene (1-hexene, 1-decene and 1-hexadecene) has been tested using combined diphenylzinc-additive initiator systems, including diphenylzinc (Ph₂Zn), a metallocene and methylaluminoxane (MAO). The metallocene were biscyclopentadienyltitanium dichloride, bis(n-butylcyclopentadienyl)titanium dichloride, cyclopentadienyltitanium trichloride and bisindenylzirconium dichloride. For Ph₂Zn-metallocene-MAO systems, titanocenes gave mainly syndiotactic homo polystyrene irrespective of the styrene/1-alkene proportion in the initial feed. Systems including Ind₂ZrCl₂ were able to copolymerize styrene 1-alkene with the copolymers incorporating alkene in a lower proportion than the present in the initial feed. Keywords: Styrene copolymerization; diphenylzinc; metallocene catalysts; tacticity. Received: 17 November 2000/Revised version: 9 May 2001/Accepted: 10 May 2001     

Silica‐supported (nBuCp)2ZrCl2: effect of catalyst active center distribution on ethylene–1‐hexene copolymerization

Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts—silica/MAO/(ⁿBuCp)₂ZrCl₂ (Catalyst 1) and silica/ⁿBuSnCl₃/MAO/(ⁿBuCp)₂ZrCl₂ (Catalyst 2), where MAO is methylaluminoxane—were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene–1‐hexene Copolymer 1 and Copolymer 2, respectively. Fouling‐free copolymerization, catalyst kinetic stability and production of free‐flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self‐nucleation and annealing experiments, as well as by an extended X‐ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO‐pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co‐monomer effect—both by 1‐hexene—were common. Each copolymer demonstrated vinyl, vinylidene and trans‐vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction of the present work, is recommended. © 2013 Society of Chemical Industry     

Polymerization of styrene by diphenylzinc-additive systems

Summary Styrene was polymerized using combined systems of diphenylzinc, Ph₂Zn, and metallocene compounds activated by methylaluminoxane, MAO. From the various metallocenes employed bis (indenyl) zirconium dichloride, Ind₂ZrCl₂, [isopropyl (cyclopentadienyl) (1-fluorenyl)] zirconiumdichloride, i-Pr (Flu) (Cp) ZrCl₂, and bis (cyclopentadienyl) titanium dichloride, Cp₂TiCl₂, produced the larger amounts of polymer. Ph₂Zn-Cp₂TiCl₂-MAO system gave polystyrene, PSt, whose DSC analysis indicated a major endotherm peak at 256°C. A butanone insoluble fraction of the polymer was separated from the crude PSt. The proportion of insoluble polymer depends on the metallocene employed and on the conversion to polymer.Partly presented at MakroAkron '94, Akron, Ohio, USA. July 1994. Part 3: cf. [13]     

Different behaviors of metallocene and Ziegler–Natta catalysts in ethylene/1,5‐hexadiene copolymerization

The behaviors of three different catalyst systems, TiCl₄/MgCl₂, Cp₂ZrCl₂ and Cp₂HfCl₂, were investigated in ethylene/1,5‐hexadiene copolymerization. In the Fourier transform infrared spectra of the copolymers, cyclization and branching were detected for 1,5‐hexadiene insertion in the metallocene and Ziegler–Natta systems, respectively. DSC and viscometry analyses results revealed that copolymers with lower T_m and crystallinity and higher molecular weight were obtained with metallocene catalysts. The sequence length distribution of the copolymers was investigated by using the successive self‐nucleation and annealing thermal fractionation technique. The continuous melting endotherms obtained from successive self‐nucleation and annealing analysis were employed to get information about short‐chain branching, the branching dispersity index, comonomer content and lamella thickness in the synthesized copolymers. The results established that metallocene catalysts were much more effective than Ziegler–Natta catalysts in the incorporation of 1,5‐hexadiene in the polyethylene structure. Metallocene‐based copolymers had higher short‐chain branching and comonomer content, narrower branching dispersity index and thinner lamellae. Finally, the tendency of the employed catalysts in the 1,5‐hexadiene incorporation and cyclization reaction was explored via molecular simulation. The energy results demonstrated that, in comparison to Ziegler–Natta, metallocene catalysts have a much higher tendency to 1,5‐hexadiene incorporation and cyclization. © 2018 Society of Chemical Industry     

(nBuCp)2ZrCl2‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure,melt behavior,and crystallization

The judicious design of methylaluminoxane (MAO) anions expands the scope for developing industrial metallocene catalysts. Therefore, the effects of MAO anion design on the backbone structure, melt behavior, and crystallization of ethylene?4‐methyl‐1‐pentene (E?4M1P) copolymer were investigated. Ethylene was homopolymerized, as well as copolymerized with 4M1P, using (1) MAO anion A (unsupported [MAOCl₂]^?) premixed with dehydroxylated silica, (ⁿBuCp)₂ZrCl₂, and Me₂SiCl₂; and (2) MAO anion B (Si?O?Me₂Si?[MAOCl₂]^?) supported with (ⁿBuCp)₂ZrCl₂ on Me₂SiCl₂‐functionalized silica. Unsupported Me₂SiCl₂, opposite to the supported analogue, acted as a co‐chain transfer agent with 4M1P. The modeling of polyethylene melting and crystallization kinetics, including critical crystallite stability, produced insightful results. This study especially illustrates how branched polyethylene can be prepared from ethylene alone using particularly one metallocene‐MAO ion pair, and how a compound, that functionalizes silica as well as terminates the chain, can synthesize ethylene?α‐olefin copolymers with novel structures. Hence, it unfolds prospective future research niches in polyethyne systhesis. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1688–1706, 2016     

Benzoyl peroxide–p‐acetylbenzylidenetriphenyl arsoniumylide initiated copolymerization of citronellol and styrene

Alternating copolymers, containing styrene and citronellol sequences, have been synthesized by radical polymerization using benzoylperoxide (BPO)–p‐acetylbenzylidenetriphenyl arsoniumylide (pABTAY) as initiator, in xylene at 80 ± 1 °C for 3 h under inert atmosphere. The kinetic expression is R_p ∝ [BPO]^0.88 [citronellol]^0.68 [styrene]^0.56 with BPO and R_p ∝ [pABTAY]^0.27 [citronellol]^0.76 [styrene]^0.63 with pABTAY, ie the system follows non‐ideal kinetics in both cases, because of primary radical termination and degradative chain transfer reactions. The activation energy with BPO and pABTAY is 94 kJ mol^?1 and 134 kJ mol^?1, respectively. Different spectral techniques, such as IR, FTIR, ¹H NMR and ¹³C NMR, have been used to characterize the copolymer, demonstrating the presence of alcoholic and phenyl groups of citronellol and styrene. The alternating nature of the copolymer is shown by the product of reactivity ratios r₁ (Sty) = 0.81 and r₂ (Citro) = 0.015 using BPO and r₁ (Sty) = 0.37 and r₂ (Citro) = 0.01 using (pABTAY), which are calculated by the Finemann–Ross method. A mechanism of copolymerization is proposed. © 2001 Society of Chemical Industry     

Copolymerization of butadiene with styrene using a rare‐earth metal compound – dialkylmagnesium – halohydrocarbon catalytic system

Copolymerizations of butadiene (Bd) with styrene (St) were carried out with catalytic systems composed of a rare‐earth compound, Mg(n‐Bu)₂ (di‐n‐butyl magnesium) and halohydrocarbon. Of all the rare earth catalysts examined, Nd(P₅₀₇)₃–Mg(n‐Bu)₂–CHCl₃ showed a high activity in the copolymerization under certain conditions: [Bd] = [St] = 1.8 mol l^?1, [Nd] = 6.0 × 10^?3 mol l^?1, Mg/Nd = 10, Cl/Nd = 10 (molar ratio), ageing for 2 h, copolymerization at 50 °C for 6–20 h. The copolymer of butadiene and styrene obtained has a relatively high styrene content (10–30 mol%), cis‐1,4 content in butadiene unit (85–90%), and molecular weight ([η] = 0.8–1 dL g^?1). Monomer reactivity ratios were estimated to be r_Bd = 36 and r_St = 0.36 in the copolymerization. © 2002 Society of Chemical Industry     

Copolymerization of tetracyclododecene or norbornene with styrene in the presence of Ni(II) complex/MAO catalytic system: First example for transition metal catalyzed copolymerization of tetracyclododecene with styrene

The first example for transition metal catalyzed copolymerization of tetracyclododecene (TD) with styrene as well as of norbornene (NB) with styrene was achieved by the use of nickel(II) complex in the presence of MAO. High cyclic olefin contents of these copolymers were showed by ¹H NMR measurements. Their GPC curves are all unimodal and M_w/M_n ratio of both homo‐ and copolymer samples are rather narrow value. These results show that these homo‐ and copolymerization take place at a single active site. The cyclic olefin content in these copolymers could be changed by changing the comonomer feed ratio. TD/styrene copolymers showed higher T_g value than that for NB/styrene copolymers and the T_g value were increases with an increase of TD content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Immobilized Me2Si(C5Me4)(N‐tBu)TiCl2/(nBuCp)2ZrCl2 hybrid metallocene catalyst system for the production of poly(ethylene‐co‐hexene) with pseudo‐bimodal molecular weight and inverse comonomer distribution

Me₂Si(C₅Me₄)(N‐tBu)TiCl₂, (nBuCp)₂ZrCl₂, and Me₂Si(C₅Me₄)(N‐tBu)TiCl₂/(nBuCp)₂ZrCl₂ catalyst systems were successfully immobilized on silica and applied to ethylene/hexene copolymerization. In the presence of 20 mL of hexene and 25 mg of butyloctyl magnesium in 400 mL of isobutane at 40 bar of ethylene, Me₂Si(C₅Me₄)(N‐tBu)TiCl₂ immobilized catalyst afforded poly(ethylene‐co‐hexene) with high molecular weight ([η] = 12.41) and high comonomer content (%C₆ = 2.8%), while (nBuCp)₂ZrCl₂‐immobilized catalyst afforded polymers with relatively low molecular weight ([η] = 2.58) with low comonomer content (%C₆ = 0.9%). Immobilized Me₂Si(C₅Me₄)(N‐tBu)TiCl₂/(nBuCp)₂ZrCl₂ hybrid catalyst exhibited high and stable polymerization activity with time, affording polymers with pseudo‐bimodal molecular weight distribution and clear inverse comonomer distribution (low comonomer content for low molecular weight polymer fraction and vice versa). The polymerization characteristics and rate profiles suggest that individual catalysts in the hybrid catalyst system are independent of each other. POLYM. ENG. SCI., 47:131–139, 2007. © 2007 Society of Plastics Engineers     

Copolymerization of styrene and butadiene with nickel compounds–methylaluminoxane catalysts

Copolymerization of styrene (St) and butadiene (Bd) with nickel(II) compound (NiX₂) in combination with methylaluminoxane (MAO) was investigated at the monomer feed ratio of 1:1. Copolymerization of St and Bd induced with NiX₂–MAO catalysts (X = acac, OCOC₆H₅, OCOC₁₈H₃₅, Cl, Cp) gave copolymers with high cis‐1,4 contents of Bd units. The St and cis‐1,4 units of the Bd units in the copolymer were not significantly affected by the X group of NiX₂, although the copolymer yields depended on the substituent. The copolymer yields depended on the solvent used for the copolymerization with the Ni(acac)₂–MAO catalyst; an aromatic hydrocarbon was more favourable than a non‐aromatic hydrocarbon. The effects of triphenylphosphine (TPP) and trifluoroacetic acid (TFA) on copolymerization of St and Bd with the Ni(acac)₂–MAO catalyst were seen the microstructure of Bd units in the copolymer. © 2001 Society of Chemical Industry     

Effects of aluminum alkyls on ethylene/1‐hexene polymerization with supported metallocene/MAO catalysts in the gas phase

The effects of aluminum alkyls on the gas‐phase ethylene homopolymerization and ethylene/1‐hexene copolymerization over polymer‐supported metallocene/methylaluminoxane [(n‐BuCp)₂ZrCl₂/MAO] catalysts were investigated. Results with triisobutyl aluminum (TIBA), triethyl aluminum (TEA), and tri‐n‐octyl aluminum (TNOA) showed that both the type and the amount of aluminum alkyl influenced the polymerization activity profiles and to a lesser extent the polymer molar masses. The response to aluminum alkyls depended on the morphology and the Al : Zr ratio of the catalyst. Addition of TIBA and TEA to supported catalysts with Al : Zr >200 reduced the initial activity but at times resulted in higher average activities due to broadening of the kinetic profiles, i.e., alkyls can be used to control the shape of the activity profiles. A catalyst with Al : Zr = 110 exhibited relatively low activity when the amount of TIBA added was <0.4 mmol, but the activity increased fivefold by increasing the TIBA amount to 0.6 mmol. The effectiveness of the aluminum alkyls in inhibiting the initial polymerization activity is in the following order: TEA > TIBA >> TNOA. A 2‐L semibatch reactor, typically run at 80°C and 1.4 MPa ethylene pressure for 1 to 5 h was used for the gas‐phase polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3549–3560, 2004     

Synthesis of high molecular weight copolymer of styrene and butadiene bearing high 1,4‐cis butadiene unit from copolymerization with CpTiCl3/methylaluminoxane catalyst

Copolymerization of styrene (St) and butadiene (Bd) with CpTiCl₃/methylaluminoxane (MAO) catalyst in the presence or absence of chloranil (CA) was investigated. The CpTiCl₃/MAO catalyst showed a high activity for the copolymerization of St with Bd. The 1,4‐cis contents in the Bd units for the copolymerization of St and Bd with the CpTiCl₃/MAO catalyst was observed, and the 1,4‐cis content was optimum at a MAO/Ti mole ratio of around 225. The effect of the polymerization temperature on the copolymerization was noted, as was the effect of the 1,4‐cis microstructure in the Bd units for the copolymerization of St and Bd. The addition of CA to the CpTiCl₃/MAO catalyst was found to influence the molecular weight of the copolymer. The high weight‐average molecular weight copolymer (M_w = ca. 50 × 10⁴) consisting of mainly a 1,4‐cis microstructure of Bd units (1,4‐cis = 80.0%) was obtained from the copolymerization with the CpTiCl₃/MAO catalyst in the presence of CA (CA/Ti mole ratio = 1) at 0°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2942–2946, 2003     

Ethylene polymerization over (nBuCp)2ZrCl2/MAO catalytic system supported on aluminosilicate SBA‐15 mesostructured materials

Heterogeneous metallocene catalysts were prepared by incipient wetness impregnation of AlSBA‐15 (Si/Al = 4.8, 15, 30, 60, and ∞) mesostructured materials with (nBuCp)₂ZrCl₂/MAO. For comparative purposes commercial silica and silica–alumina (Si/Al = 4.8) supports were also impregnated with the MAO/metallocene catalytic system. A combination of X‐ray powder diffraction, nitrogen adsorption–desorption isotherms at 77 K, transmission electron microscopy, ICP‐atomic emission spectroscopy, and UV–vis spectroscopic data, were used to characterize the supports and the heterogeneous catalysts. Ethylene polymerizations were carried out in a schlenk tube at 70 °C and 1.2 bar of ethylene pressure. The polyethylene obtained was characterized by GPC, DSC, and SEM. Catalysts prepared with mesostructured SBA‐15 supports exhibited better catalytic performance than those supported on amorphous silica and silica–alumina. In general, higher ethylene polymerization activity was achieved if (nBuCp)₂ ZrCl₂/MAO catalytic system was heterogenized using supports with lower pore size in the range of the mesopores and lower Si/Al ratio. All catalysts produced high‐density polyethylene, with high crystallinity values and fibrous morphology when SBA‐15 mesostructured materials were used as supports. POLYM. ENG SCI., 2008. © 2008 Society of Plastics Engineers     

An improved phase‐inversion process for the preparation of silica/poly[styrene‐co‐(acrylic acid)] core–shell microspheres: synthesis and application in the field of polyolefin catalysis

Spherical and well‐dispersed silica/poly[styrene‐co‐(acrylic acid)] (SiO₂/PSA) core–shell particles have been synthesized using an improved phase‐inversion process. The resulting particles were successfully used as supports for polyolefin catalysts in the production of polyethylene with broad molecular weight distribution. Through the vapor phase, instead of the liquid phase in the traditional process, a non‐solvent was introduced into a mixture of micrometer‐sized SiO₂ and PSA solution. The core–shell structure of the resulting SiO₂/PSA microspheres was confirmed using optical microscopy, scanning electron microscopy, Fourier transfer infrared spectrometry, thermogravimetric analysis and measurement of nitrogen adsorption/desorption isotherms. In order to avoid agglomeration of particles and to obtain a good dispersion of the SiO₂/PSA core–shell microspheres, the non‐solvent was added slowly. As the concentration of PSA solution increased, the surface morphology of the core–shell particles became looser and more irregular. However, the surface area and the pore volume remained the same under varying PSA concentrations. The SiO₂/PSA core‐shell microspheres obtained were used as a catalyst carrier system in which the core supported (n‐BuCp)₂ZrCl₂ and the shell supported TiCl₄. Ethylene/1‐hexene copolymerization results indicated that the zirconocene and titanium‐based Ziegler–Natta catalysts were compatible in the hybrid catalyst, showing high activities. The resulting polyethylene had high molecular weight and broad molecular weight distribution. Copyright © 2010 Society of Chemical Industry     

Investigation of styrene/1‐hexene copolymerization by homogeneous and heterogeneous bisindenyl ethane zirconium dichloride catalyst system

Homogeneous copolymerization of styrene and 1‐hexene was carried out in toluene at room temperature using bisindenyl ethane zirconium dichloride/methylaluminoxane (MAO). The supported catalyst was prepared with immobilization of Et(Ind)₂ZrCl₂/MAO on silica (calcinated at 500°C) with premixed method. Heterogeneous copolymerization of styrene/1‐hexene with different mole ratios was carried out in the presence of supported catalyst system. The copolymers obtained from homogeneous and heterogeneous catalyst system were characterized by ¹H NMR and ¹³C NMR. Composition of the resulting copolymers was determined by ¹H NMR data. Analysis of ¹³C NMR spectra of obtained copolymers by homogeneous and heterogeneous catalyst systems present isotactic olefin‐enriched copolymers. Molecular weight and thermal behavior of resulting copolymers was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4008–4014, 2007     

Ethylene polymerization with methylaluminoxane/(nBuCp)2ZrCl2 catalyst supported on silica and silica‐alumina at different AlMAO/Zr molar ratios

Methylaluminoxane (MAO)/(nBuCp)₂ZrCl₂ metallocene catalytic system was supported on silica and silica‐alumina. The Zr loading was varied between 0.2–0.4 wt %, and the MAO amount was calculated to get (Al_MAO/Zr) molar ratios between 100 and 200, suitable for the industrial ethylene polymerization of supported metallocene catalysts. Catalytic activity was statistically analyzed through the response surface method. Within the ranges studied, it was found that Zr loading had a negative effect on polymerization activity, which increases with the (Al_MAO/Zr) molar ratio. Catalysts supported on silica‐alumina are more active than those supported on silica, needing less MAO to reach similar productivity, which constitutes an important advantage from an economical and environmental point of view. Supported catalysts were characterized by ICP‐AES, SEM‐energy‐dispersive X‐ray spectrometer, and UV‐Vis spectroscopy, whereas polyethylenes were characterized by GPC and DSC. Molecular weight and crystallinity are not influenced by Zr loading or (Al_MAO/Zr) ratio, in the range studied. In general, silica‐supported MAO/(nBuCp)₂ZrCl₂ catalysts give polyethylenes with higher molecular weight and polydispersity but lower crystallinity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Nitroxide‐mediated homopolymerization and copolymerization of 2‐vinylpyridine with styrene

Homopolymerization and copolymerization of 2‐vinylpyridine (2VP) with styrene (S) at 125°C in the presence of 2,2,6,6‐tetramethyl piperidin‐1‐yloxyl (TEMPO) radicals have been studied. The homopolymerization was carried out with 2,2′‐azobis(isobutyronitrile) (AIBN) as a thermal initiator or without AIBN in the initial reaction mixture. In the copolymerization initiated with AIBN, the molar fraction of 2VP in the feed, F_2VP, varied in the range of 0.1–0.9; F_2VP = 0.65 was found to be the azeotropic composition. The linear semilogarithmic time–conversion plots demonstrated a pseudoliving nature of the polymerizations under study. The molecular weight–conversion dependences indicated the participation of side reactions, diminishing the number of TEMPO‐terminated polymer chains. The synthesized homopolymers and copolymers were characterized using size‐exclusion chromatography (SEC), nitrogen analysis, and NMR spectroscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2024–2030, 2001     

Effect of GMA on monodisperse epoxy‐functionalized polymer microsphere particles by dispersion copolymerization of styrene with glycidyl methacrylate

Monodisperse poly[styrene‐co‐glycidyl methacrylate (GMA)] microparticles were synthesized by dispersion copolymerization in a water–ethanol medium. The effects of various polymerization parameters on the particle size and size distribution of the dispersion copolymerization were investigated. The dispersion of polymer particles decreased when the GMA was added if the polystyrene homopolymer particles were polydispersed. The GMA acted as a comonomer as well as a costabilizer in the dispersion copolymerization of styrene with GMA. The solvency of the monomer increased with the concentration of GMA in the polymerization medium because GMA has a greater hydrophilicity than styrene, resulting in a large particle size and a slow polymerization rate. From an HCl–dioxane analysis of the poly(styrene‐co‐GMA) microparticles, great amounts of epoxy groups were detected after the completion of dispersion copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1206–1212, 2001